In color television tubes, color purity relies mainly on alignment of the guns, the aperture mask, and the phosphor pattern developed on the screen. Impurity results when the alignment established during the phosphor pattern development is not retained in the operating tube. One of the principal errors is incorrect Q space in the operating tube caused by changes in the shape of the glass or mask or both during processing. The error is most pronounced and most evident in the corners of the picture.
In a conventional color television picture tube 10 illustrated in FIGS. 1a and 1b labeled as Prior Art. A TV panel 11 has a peripherally located integral skirt 12 which mates along a seal 13 with a funnel portion 14. An aperture mask 15 of conventional design is mounted in a frame 16 which is in turn oriented in an xy direction (FIG. 1a) and at a selected Q spacing (FIG. 1b) from the panel 11 by clips 17 welded to the frame 16. The clips 17 have a free end each engaging a stud 18 which in turn is mounted in the panel skirt 12.
Typically the studs 18 are fabricated from metal pins, which are fused in the panel skirt 12. The equipment necessary for mounting and locating the studs 18 is expensive and is sometimes a source for tube rejects.
Many variations of the prior art arrangement illustrated in FIGS. 1a and 1b exist, however th systems are characteristic, in that, they use some sort of stud arrangement which is fused to the glass for supporting the aperture mask 15 and frame 16.
The present invention minimizes errors which results from the arrangement illustrated in FIGS. 1a and 1b, and eliminates the need for studs 18 and the equipment necessary to install them. Furthermore, losses associated with the stud seal arrangement and advantages of the present invention provide for a less costly and more efficient aperture mask mounting system.